http://www.latimes.com/nation/la-na-missile-defense-signing-...
"One struck the word “limited” from language describing the mission of the country’s homeland missile defense system. The system is designed to thwart a small-scale attack by a non-superpower such as North Korea or Iran."
The real fear is that a small country will acquire missiles with nukes. It's really only a matter of time, a decade perhaps. The upside of technology advancing is that a private company will get to Mars. The downside is that a lot more countries will have the technology for military use.
Wars don't happen when there's an obvioua military superiority at one of the sides. US's unipolar world has lead to unique peace in the world.
We've gotten rid of most of the nuke stockpile, at least.
> why not spend an exorbitant amount of money to point an even bigger one
Huh? This is an intercept system, not a weapon.
The gun here is America's nukes. America currently can't really even think about using its nukes because of MAD. With a functioning nuclear defence system, America doesn't have to worry about MAD and can use its nukes without worrying about retribution, which makes them a bigger threat, hence a bigger weapon.